In many of today's computers, commands are entered into the computer by using a mouse pointing device. Typically, the mouse includes a housing partially enclosing a rotatable ball and one or more depressable buttons. As the mouse is moved along a surface, oftentimes a table top, transducers within the mouse sense the ball's rotation and generate signals output to the computer. The signals control a corresponding movement of a cursor, or pointer, on a visual display of the computer. Depending upon the location of the cursor on the visual display, a variety of commands can be entered into the computer by depressing the buttons and actuating switches positioned within the housing. Examples of such commands include launching an application program, pulling down a menu, opening a document, selecting a portion of a document for editing, and creating terminal or other points in a graphic pattern on the visual display.
Today's commercially available mice are assembled from a relatively large number of pieces. Generally, the greater the number of parts in a mouse the more expensive it is to produce. This is because both the number of manufacturing and assembly steps increase with the increasing number of parts. For example, most of today's mice have an upper housing, or case top, assembled from at least two pieces, with the buttons being formed from a separate piece that must be attached to the rest of the case top. While one-piece case top mice are currently available on the market, they require additional pieces within the housing to accommodate the one-piece case top design, and so there is no overall parts reduction. Also, the currently available one-piece piece case top mice have an unsatisfactory limitation on button movement. Currently available mice have the upper and lower parts of the housing fastened together by two or more screws. Currently available mice have switches assembled from a number of separate pieces. Currently available mice have a multi-piece means of biasing the ball against transducers.
Overall, it is desirable to design a mouse pointing device that can be manufactured from as few pieces and in as few manufacturing and assembly steps as possible, without sacrificing the requisite operating characteristics and durability.